Depending on the age of your IRMS system, different types of
noises abound.
         Yes, direct drive pump noise is a problem on older systems with
diffusion pumps.
         However, I find that our new IRMS systems (be it Finnigan or be it
Europa) have the predominant noise coming from the turbo pumps and fans for
cooling electronics & the turbos.  That noise is a high pitched whine that
does not go away w/ putting direct-drive pumps in another room.  Most of us
simply put up w/ this noise be it by an inside-your-head filter or ear
plugs (if you can't do yoga).

         -Dwight Matthews

---------------------------------------
Dwight E. Matthews, Ph.D.
Professor of Medicine and Chemistry
The University of Vermont
Department of Medicine
Given Bldg -  B217
Burlington, VT 05405
tel: 802 656-8114  FAX: 802 656-1229
email:  [log in to unmask]
http://www.uvm.edu/~dmatthew/
---------------------------------------